Patent GB-190116221-A (GB)
Title: Improvements in or relating to Variable Speed Gears for Bicycles and other Machinery.
Inventor: STURMEY JOHN JAMES HENRY
Filed: 1901-08-13
Granted: 1902-08-07
Abstract: 16,221. Sturmey, J. J. H. Aug. 13. Driving-mechanism.- Relates to three-speed epicyclic gearing for bicycles &c. The chainwheel 22 is mounted on the cylinder 23 ; a similar cylinder 24 is fixed to the hub 26 of the bicycle wheel, which encloses a cylinder 36 formed with clutch jaws 48, 49 and with a ring of internal teeth 66. These teeth gear with a pinion 3, fixed to the stationary spindle 2, by means of pinions 35 mounted in a loose carrier 32, 33, which is formed with clutch jaws 46, 47. Sliding jaw clutches 37, 42 work through slots in the cylinders 23, 24 and are united by keys 16, 17 to a rod 4, which is movable lengthways in the stationary spindle. When the rod is in its extreme position to the left, the clutch 37 couples the sleeve 23 to the carrier and a high speed is imparted to the cylinder 36, which is coupled by the clutch 42 to the cylinder 24 of the hub. When the rod is moved to the right, the clutch 37 couples the cylinder 33 directly to the hub by means of clutch jaws formed thereon. Upon further movement in the same direction, the clutch 37 couples the cylinder 36 to the cylinder 23, and the clutch 42 couples the carrier to the cylinder 24 of the hub, which is then driven at the low speed. The rod 4 is built up of two end parts 61, 63 secured together by a stem on the one screwing into a socket in the other, and a distance piece 64 ; the keys 16, 17 are clamped between the distance piece and the ends of the parts 61, 63. The rod is forced in one direction by a spring 5, and is drawn in the other by a cord connected to a handle in a suitable position. In a modification, the clutch 37 is made with a single set of jaws instead of two as shown, and the mid gear is obtained through the sleeve 36, which acts as a coupling between the clutches 37, 42. In this case, the pinion 3 may be free on the spindle and be held stationary for the high and low speeds only by forming recesses in the clutches to engage jaws on the end of a sleeve upon which it is mounted ; the gear rotates as one piece at the middle speed. In the modification shown in Fig. 6, sliding rods 76, 78 coupled by rocking levers 90 and a ring 86 are used instead of clutches. In the position shown, the carrier is locked to the chain-wheel 22 by the rods 76, and the internal wheel 36 to the hub 26 by the rods 78. In the other extreme position the rods 76 engage with the hub, and the rods 78 with the flanged disc 72 on the chain-wheel. In the mid position, the parts are locked, but the central pinion is free ; in the other positions, the pinion is locked to the stationary spindle by the engagement of the keys 16, 17 with slots in the end of its sleeve. In another arrangement, Fig. 7, the planet pinions are mounted on the hub, and the internal wheel and the central pinion are both free ; the chain-wheel may drive either or both of these parts by means of spring pawls, or either may be held stationary by means of spring plungers adapted to engage with stops formed thereon and to press the spring pawl out of engagement. When the chain-wheel drives both, the gear is locked and the hub is driven at the same speed. By locking the internal wheel and driving the central pinion, the high speed is obtained ; the low speed follows the locking of the pinion and the driving of the internal wheel. The two plungers are connected by cords to handles which are coupled together by a cord passing over a pulley, so that each may be moved in one direction without affecting the other, while movement of one in the other direction is accompanied by a reverse movement of the other. In another modification, Fig. 11, the planet pinions, carried on the hub, are double and gear with two central pinions and with an internal wheel on the chainwheel. Either of the central pinions may be held stationary, or they may be locked together, by means of a clutch arrangement, and allowed to rotate.